SMD refers to the method for attaching electronic components on the circuit boards. SMD stands for Surface Mounted Device (e.g. for the components placed on the surface of the board). It is also known as SMT: Surface Mounted Technology. This method is carried out exclusively with computer-controlled placement/attachment machines.

Lumen (lm)

The lumen is the physical unit of the luminous flux (light quantity) in the visible range. This unit is based on the sensitivity of the human eye; the luminous flux values of differently coloured light sources differ significantly even when they have the same energy content. So, in particular for red and blue LEDs, the energy content of the transmitted light (PAR value) or the wavelength is specified instead of the luminous flux.

Lux (lx)

Lux is the unit of illumination intensity based on a point-shaped light source. This is expressed in lm/m2. A cloudless night with full moon can achieve a maximum of 1 lx. A bright sunny day, however, can reach 100,000 lx.


The CRI (Colour Rendering Index) indicates the quality of the colour reproduction, in relation to a reference light source of the same colour temperature. A high colour rendering index is not equivalent to a good reproduction of all colours. Good CRI values are > 80.

Light colour

The light colour primarily reflects the subjective colour impression made by the human eye. This means that light colours such as warm white, neutral white or daylight can also be generated in the white light range. These names already allow a rough orientation towards the colour temperature.

Colour temperature

The colour temperature is used to quantitatively determine the colour impression of a light source. The colour temperature is specified in K (Kelvin); it is based on the temperature of the Plank radiator in combination with the light emitted. The spectral compositions may vary significantly at the same colour temperature.

Colour location

Normally, the colour location is represented in a simplified 2-dimensional chart by the x and y coordinates in the CIE colour triangle.


Efficiency is a key parameter for evaluating and comparing the effective energy consumption of an LED in the white light range. This value is specified in Im/W. The higher this value, the more energy-efficient the light source.


Light visible to the human eye is usually composed of different wavelengths in the range of 380 to 780 nm. By shifting the spectral components, almost any desired light colour may be generated.


The lifespan of an LED indicates the time period after which the LED still supplies 70% of its initial output. This is not equivalent to the failure of the LED.


This designation indicates the degree of protection of an electrical device. The numerical combination stands for the degree of protection against the penetration of foreign bodies (the first digit) and against the penetration of water (the second digit). The higher the value of the respective digit, the higher the protection and better the seal. IP67 = International Protection; 6 = dust-proof; 7 = protection against intermittent submergence.


LED is an abbreviation for Light Emitting Diode. The wavelength of the light emitted is dependent on the material of the semiconductor (diode) being used.

Kelvin (K)

This is a physical unit of temperature. Also refer to „Colour temperature“.